1. Field of the Invention
This invention pertains generally to delivery of medicinal aerosols, and more particularly to a system for delivering medicinal aerosols to a patient through an endotracheal tube.
2. Description of the Background Art
It is known that the thin membrane of the lungs can be easily penetrated by medicinal aerosols and provides a convenient and generally safe vehicle for obtaining rapid absorption of medication by the body. Medication or drugs are generally delivered to the lung membrane in the form of a fine mist or aerosol which is breathed into the lungs through the nose or mouth of the patient. Quite typically, a nebulizer is used to convert a liquid into a fine aerosol, and the aerosol is introduced into the lungs through an endotracheal tube.
Delivery of medicinal aerosols in this manner is most commonly made through an endotracheal tube connected to a "patient wye." Referring to FIG. 1, which schematically shows a known configuration, a patient wye 10 typically has an inhalation port 12 which is connected to an inhalation tube 14, an exhalation port 16 which is connected to an exhalation tube 18, and an endotracheal port 20 which is connected to an endotracheal tube 22. Inhalation tube 14 and exhalation tube 18 are connected to a ventilator, respirator, or the like. An aerosol supply hose 24, which is connected to a nebulizer or other device for generating a continuous flow of medicinal aerosol, is connected to input port 12.
When medicinal aerosol is delivered directly to inhalation port 12 of patient wye 10 in this manner, the ventilator will ventilate the patient by providing a constant airflow in the inhalation tube 14 and periodically inflating the patient by occluding the flow through the exhalation tube 18. In this configuration, the medicinal aerosol is diluted by the inhalation flow coming from the ventilator. In addition, approximately ninety percent of the medicinal aerosol is wasted because it continues to be administered during exhalation and, therefore, passes into the exhalation tube 18 where it is lost.
As can be seen, therefore, a need exists for an aerosol delivery system which administers medicine during the inhalation cycle and stores medicine during the exhalation cycle. The present invention satisfies that need and significantly increases the efficiency of delivery of medicinal aerosol.